Whether it's too late depends on your first frost date and what you're planting
You can plant tomatoes as long as you have 50 to 85 frost-free days left before your first fall frost. Determinate varieties (bush types that fruit all at once) need about 50 to 70 days. Indeterminate varieties (vining types that produce until frost) need 70 to 85 days. If your first frost date is October 15 and today is August 1, you have 75 days left — enough for most indeterminate types but tight for late-season varieties.
The real cutoff is not a calendar date but a calculation: count backward from your first frost date. If fewer than 50 days remain, starting from seed is too late. Transplants (seedlings already 6 to 8 weeks old) can work if you have 50 to 60 days left, because they skip the germination and early growth phase. Seeds need those extra weeks.
Your first frost date is specific to your location. You can find it through the USDA Plant Hardiness Zone Map (search your zip code) or by asking your local cooperative extension office. Do not guess based on a neighboring state or a general region — frost dates vary by elevation and proximity to water.
Key Takeaways
- Count the frost-free days remaining from today until your first fall frost date; if fewer than 50 days remain, planting from seed will not work.
- Transplants (young plants from a nursery) can go in the ground if you have 50 to 60 days left, but seeds need 70 to 85 days depending on variety.
- Determinate (bush) tomatoes mature faster than indeterminate (vining) types, so they are your only option if time is short.
- Your first frost date is location-specific and available through the USDA Hardiness Zone Map or your local cooperative extension.
- Even if you plant late, a frost cloth or row cover can extend your harvest by a few weeks if an early frost threatens.
How to find your first frost date
The USDA Plant Hardiness Zone Map is the standard reference. Go to planthardiness.ars.usda.gov, enter your zip code, and the map will show your zone. Below the zone number, you will see your average first fall frost date. Write this date down — you will use it to plan any late plantings for the rest of the season.
Your local cooperative extension office (run by your state's land-grant university) also has this information and can answer questions specific to your area. Search "[your state] cooperative extension" plus your county name to find the office nearest you. They often have printed frost-date calendars and can tell you which varieties do well in a late planting.
If you live in a microclimate — a valley, near a large lake, or on a south-facing slope — your actual frost date may differ from the official one by a week or two. Neighbors who have gardened in your exact spot for years are often more reliable than the map for these small areas.
Determinate varieties are faster if you are running out of time
Determinate tomatoes (also called bush or paste tomatoes) grow to a fixed size, flower all at once, and produce most of their fruit within a narrow window — usually 50 to 70 days from transplant. Varieties like 'Roma', 'San Marzano', and 'Mountain Magic' are determinate. They are the only choice if you have fewer than 70 days left.
Indeterminate varieties (like 'Brandywine', 'Cherokee Purple', and 'Sungold') keep growing and producing until frost kills them. They need 70 to 85 days to start producing and will keep flowering and fruiting for weeks after that. If you plant them late, you may get only one or two harvests before frost arrives.
Seed packets and nursery labels always list days to maturity. Look for the phrase "days to first fruit" or "days to maturity" — this is the number of days from transplant (not from seed) to the first ripe tomato. If the label says 65 days and you have 70 days left, you will harvest, but barely.
Transplants work better than seeds if time is short
A transplant is a seedling that has already spent 6 to 8 weeks growing indoors. When you buy one from a nursery, it is already past the slowest part of its life. Planting a transplant cuts 6 to 8 weeks off the timeline compared to starting from seed.
If you have 50 to 60 days left, buy transplants instead of seeds. Choose determinate varieties and look for plants that are already flowering or have flower buds visible. A plant with buds will set fruit faster than one that is still purely vegetative.
Transplants are more expensive per plant than seeds, but you need fewer of them and you will actually harvest fruit. A packet of seeds costs $3 to $5 and produces dozens of plants; a transplant costs $4 to $8 but is ready to produce now.
Soil and sunlight matter more when you are planting late
Late-planted tomatoes need full sun (at least 6 to 8 hours daily, ideally 8 to 10) and warm soil. If your garden is shaded by trees or buildings in late summer, tomatoes will slow down and may not ripen before frost. Check the light in your planting spot at 9 a.m., noon, and 3 p.m. to be sure.
Soil temperature matters more than air temperature. Tomato roots grow slowly in soil below 60°F and stop growing below 50°F. If your soil is cool, warm it up by laying black plastic or landscape fabric over the bed for a week before planting. This traps heat and raises soil temperature by 5 to 10 degrees.
Add compost or aged manure to the planting hole. Late-season tomatoes are racing against time and need readily available nutrients. A plant in poor soil will spend weeks establishing roots instead of flowering.
Frost cloth and row covers can buy you extra weeks
If an early frost threatens before your tomatoes are ripe, a frost cloth or row cover can protect them for a few degrees and a few weeks. Frost cloth is lightweight fabric that lets light and water through while trapping heat. Drape it over the plants when frost is forecast and remove it during the day if temperatures rise above 50°F.
Row covers work the same way but are more permanent. You can leave them on for weeks if nights stay cold. They reduce light slightly, so remove them once nighttime temperatures stay above 50°F consistently.
These methods buy you time but do not replace a long growing season. If you have only 40 days left, frost cloth will not ripen a 70-day variety. It extends the season by a few weeks, not months.
What to do if you have missed the window entirely
If fewer than 40 days remain and you do not have a frost cloth or row cover, tomatoes will not produce enough fruit to be worth planting. The plant will flower, but fruit will not have time to ripen before frost kills it.
Instead, grow fast crops: lettuce, spinach, arugula, and radishes all mature in 30 to 45 days and tolerate cool weather. Kale and chard produce for weeks and improve in flavor after a light frost. These are better uses of your remaining growing season.
If you want tomatoes next year, start seeds indoors 6 to 8 weeks before your last spring frost date. This is the standard timeline and gives plants the full season they need. Mark your calendar now so you do not miss the window in spring.
Frequently Asked Questions
Can I plant tomatoes in late August or early September?
Yes, if your first frost date is at least 60 days away and you buy transplants rather than seeds. Late August works in zones 7 and warmer. In zones 5 and 6, early September is usually too late unless you have a frost cloth ready. Check your specific frost date before buying plants.
What if I plant late and the tomatoes are still green when frost comes?
Pick the green tomatoes before frost kills the plant. Wrap them in newspaper and store them in a cool room (60 to 70°F). They will ripen slowly over two to four weeks. They will not taste as sweet as vine-ripened fruit, but they will be edible.
Do cherry tomatoes ripen faster than slicing tomatoes?
Usually yes. Most cherry tomato varieties mature in 60 to 75 days, while slicing varieties need 70 to 85 days. Check the seed packet or label for the specific variety, because some cherry types are slow and some slicing types are fast.
Can I plant tomatoes in a container if I am running out of time?
Yes. Containers warm up faster than garden soil and can be moved to a warmer spot or under cover if frost threatens. Use a pot at least 5 gallons for determinate varieties and 10 gallons for indeterminate types. Fill it with potting mix (not garden soil) and plant a transplant, not a seed.
What if my area gets an unexpected early frost?
If frost is forecast and your tomatoes are still growing, cover them with frost cloth, old sheets, or blankets the night before. Remove the cover the next morning once temperatures rise. This can protect plants from a light frost (28 to 32°F) but not a hard freeze (below 28°F).